During the total solar eclipse on Aug. 21, NASA’s Lunar Reconnaissance Orbiter, or LRO, captured an image of the Moon’s shadow over a large region of the United States, centered just north of Nashville, Tennessee.

As LRO crossed the lunar south pole heading north at 3,579 mph (1,600 meters per second), the shadow of the Moon was racing across the United States at 1,500 mph (670 meters per second).

A few minutes later, LRO began a slow 180-degree turn to look back at Earth, capturing an image of the eclipse very near the location where totality lasted the longest. The spacecraft’s Narrow Angle Camera began scanning Earth at 2:25:30 p.m. EDT (18:25:30 UTC) and completed the image 18 seconds later.

This animation begins with the black-and-white image of the Moon’s shadow on Earth, as seen by NASA’s Lunar Reconnaissance Orbiter, or LRO. The levels of gray in the image are gradually adjusted, saturating the background until the features of the landscape disappear. At that point, it’s possible to see the edge of the total solar eclipse. As the gray levels are restored, the umbra, or the completely shadowed area, becomes visible, followed by the penumbra, or partial shadow where part of the Sun peaks over the edge of the Moon.LRO’s Narrow Angle Camera can record 3600 gray levels, whereas most digital cameras record only 255 levels of gray. The camera was designed this way because the Moon is a high-contrast target, with very bright materials next to dark materials. In these images, those 3,600 levels of gray were squeezed into 255 levels because that’s what a typical computer screen is capable of displaying.